Vertical Walking, an experimental prototype by Rombout Frieling Lab designed "to move ourselves between floors in a building," exploits the potential of the human body, materials and intelligent design to require less than 10% of the effort required by taking a flight of stairs – and without the need for any sort of ancillary power supply. The ultimate aim of the designers is to allow people to "move harmoniously through our vertical habitats of the future."

The designers acknowledge that the price of urban land is "skyrocketing." With a further three billion people expected to move into urban environments in the decades to come, they argue that we will be forced to exploit vertical space: "more and taller towers [and] the use of attics and roofs." At the same time, the global population is ageing; "staircases are becoming major bottlenecks." Elevators, they state, rely on significant amounts of external power, while depriving us from daily exercise.

According to its designers the prototype has been successfully tested by a wide range of users, including those suffering from Multiple Sclerosis (MS).